DESCRIPTION OF THE PRIOR ART
Radiometric and fluorometric methods for identifying and measuring allergy specific IgE levels in patient serum are commercially available and are known as the RAST test, for example. U.S. Pat. Nos. RE-29,474; 3,555,143; 3,648,346; 3,720,760 and 3,966,898 relate to these methods and reagents therefor. Enzymatic immunological methods for identifying and quantifying antigens and antibodies in liquids are widely used and are known as the ELISA and EIA tests, for example. Basic technology for enzymatic assays and reagents therefor are disclosed in U.S. Pat. Nos. RE-29,169 and 3,839,153, for example.
A review of the current state of the art with regard to immunoassays for the detection of proteins in solutions is provided by R. Rose et al, Manual of Clinical Immunology, 2nd ed. American Society for Microbiology, Washington, pp 327-429, 775-849 (1980) and by A. Voller et al, Immunoassays for the 80's, University Park Press, Baltimore (1981), and the publications cited in both of these publications, the entire contents all of which are hereby incorporated by reference. The chapter of Immunoassays for the 80's, supra, by T. A. E. Platts-Mills et al, titled "Radio-immunoassays in Allergy", pp 289-311, and the publications cited therein provide a comprehensive review of allergy tests.
Procedures for standardizing allergens are summarized by Rose et al in Manual of Clinical Immunology, supra, pp 778-788, and the citations therein. In one RAST approach, allergen of unknown potency is coupled to a solid support, and the quantity required to give a certain degree of reactivity in the RAST test has been determined. In a second approach termed "RAST inhibition", the allergen of unknown potency is incubated with standardized allergen coupled to a solid support and reagent IgE specific to the allergen, and competitive binding occurs. In both procedures, the bound IgE is determined with radiolabeled IgG specific to IgE, and the results are compared to those obtained with the procedure using reference allergens of known potency. Both procedures have limited accuracy, however. Partially because of the wide discrepancies found in tests of the same material (test limitations) and the crude, highly variable extracts of very limited stability usually administered (reagent variability), mandatory potency standards have not yet been adopted by regulatory agencies.
Procedures for binding proteins to insoluble supports have been previously described. Antibodies have been covalently bonded to insoluble supports as described in U.S. Pat. Nos. 3,551,555, 3,553,310, 4,048,298 and RE-29,474. Binding of antibodies to polystyrene by adsorption has been described in U.S. Pat. Nos. 3,646,346 and 4,092,408, for example. Allergens have been covalently bonded to a variety of insoluble supports as described in U.S. Pat. No. 3,720,760.
Polyethylene glycol has been used in protein fractionation processes described by A. Polson et al, Biochim. Biophys Acta, vol. 82, pp 463-475 (1964) and A. Polson et al, Vox Sang, vol. 23, pp. 107-118 (1972).